Not necessarily. In the first 2 of my involuntary downgrades this trip, the flight is 1-class (was 2-class when ticketed) and while there is another airline operating the route it is with another alliance. On a full fare ticket a transfer to the other airline is feasible, but on xONEx which are discounted tickets it depends on the goodwill of the ticketed airline.

In my case, Comair did consider putting me on South African (but only after I asked if this was an option). But schedules and my tight timing precluded me taking the option up. I did get a voucher as compensation for 1 flight, but it is a token amount. For the 2nd flight check in was by contract agents who were not authorised to deal with compensation so I am waiting to be contacted by Comair.

I still have several more invol downgrades on this DONE4 ticket and will report how those go as I come to them.